Method and apparatus for generating oscillating signals

ABSTRACT

An apparatus for generating an oscillating signal that includes a circuit to accelerate the time in which an oscillating signal reaches a defined steady-state condition from a cold start. The apparatus includes an oscillating circuit to generate an oscillating signal; a first circuit to supply a first current to the oscillating circuit; and a second circuit to supply a second current to the oscillating circuit, wherein the first and second currents are adapted to reduce the time duration for the oscillating signal to reach a defined steady-state condition. The apparatus may be useful in communication systems that use low duty cycle pulse modulation to establish one or more communications channels, whereby the apparatus begins generating an oscillating signal at approximately the beginning of the pulse and terminates the oscillating signal at approximately the end of the pulse.

FIELD

This disclosure relates generally to generating oscillating signals, andin particular, to reducing time for an oscillating signal to reach adefined steady-state condition.

BACKGROUND

Previous communication systems use techniques that are generally powerinefficient. These systems typically employ transmitters and receiversthat may require continuous power even during times when they are nottransmitting or receiving communications. Such systems that remain idlewhile still consuming power are typically inefficient from a powerperspective.

In some applications, power inefficient communication devices maypresent limitations as to their continuous use. For example, portablecommunication devices that rely on battery power generally providerelatively short continuous operation before the battery needs to bereplaced or recharged. In some situations, this may result in adverseconsequences, such as data loss, communication delays, dropped sessions,and down time.

On the other hand, communication systems that consume substantiallylower power during idle times are able to operate for longer periodswith a limited power source. Thus, communication systems that power on atransmitter only when the signal is to be transmitted will generallyconsume less power than a transmitter that is continuously powered.Similarly, communication systems that power on a receiver only when thesignal is to be received will generally consume less power than areceiver that is continuously powered.

A pulse modulator may be used to control the times for transmitting andreceiving signals. In this regard, a pulse modulator may power on atransmitter local oscillator (LO) for transmitting a signal only for theduration of a pulse. Similarly, a pulse modulator may power on areceiver LO for receiving a signal only for the duration of a pulse. Inthis capacity, the LO generates and sustains an oscillating signalwithin the duration of each pulse. If the pulse width is relativelyshort, such as in a low duty cycle application, the LO should respondquickly to generate a sufficiently stable oscillating signal.

SUMMARY

A summary of sample aspects of the disclosure follows. For convenience,one or more aspects of the disclosure may be referred to herein simplyas “some aspects.”

Some aspects of the disclosure relate to an apparatus for generating anoscillating signal. The apparatus comprises a first circuit to generatean oscillating signal, a second circuit too supply a first current tothe first circuit; and a third circuit to supply a second current to thefirst circuit, wherein the first and second currents are adapted toreduce the time duration for the oscillating signal to reach a definedsteady-state condition.

In some aspects, the apparatus may be configured as a voltage controlledoscillator (VCO). In this regard, the second circuit may be configuredas a boost bias circuit to accelerate the time in which an oscillatingsignal reaches a defined steady-state condition from a cold start. Thisis particularly useful in communication systems and devices that use lowduty cycle pulse modulation to establish one or more communicationschannels. In such applications, the VCO, serving as a local oscillator(LO), begins generating an oscillating signal at approximately thebeginning of the pulse and terminates the oscillating signal atapproximately the end of the pulse. For improved communicationperformance, the oscillating signal should reach a defined steady-statecondition within a relatively short time period as compared to the widthof the pulse.

In some aspects, the VCO comprises an oscillating circuit to generate anoscillating signal; a quiescent bias circuit to supply a quiescentcurrent to the oscillating circuit; and a boost bias circuit to supply aboost current to the oscillating circuit, wherein the boost current andthe quiescent current are adapted to reduce the time duration for theoscillating signal to reach a defined steady-state condition.

In some aspects, the first circuit of the apparatus may comprise a tankcircuit coupled to a negative resistance generator. The tank circuit, inturn, may comprise an inductive element coupled to a capacitive element.The capacitive element may comprise a programmable switched capacitorbank for tuning the frequency of the oscillating signal.

In some aspects, the apparatus may further comprise a steady-statedetector adapted to disable the third circuit from supplying the secondcurrent to the first circuit in response to detecting the definedsteady-state condition of the oscillating signal. Thus, the thirdcircuit may only be used upon start up to quickly achieve the definedsteady-state condition of the oscillating signal. The definedsteady-state condition of the oscillating signal may specify a stabilityrequirement for the amplitude and/or frequency of the oscillatingsignal.

In some aspects, the apparatus may further comprise a frequencycalibration unit adapted to tune the first circuit so that theoscillating signal cycles within a defined frequency range. In somecommunications systems, such as energy detection systems, the frequencyof the LO need not be that precise. For example, the defined frequencyrange may be up to five (5) percent of a defined center frequency. Thefrequency calibration unit may be adapted to calibrate or tune the firstcircuit upon power up, upon detecting an ambient temperature changeabove a defined threshold, and/or upon receiving a new frequencyspecification for the oscillating signal.

In some aspects, one or more apparatuses may be used as localoscillators (LOs) in communication systems and devices to up convert anddown convert signals. For example, the apparatus may be used toestablish one or more ultra-wide band (UWB) channels for communicatingwith other devices using pulse division multiple access (PDMA), pulsedivision multiplexing (PDM), or other types of pulse modulationtechniques. A UWB channel may be defined as having a fractionalbandwidth on the order of 20% or more, a bandwidth on the order of 500MHz or more, or both. The fractional bandwidth is a particular bandwidthassociated with a device divided by its center frequency. For example, adevice according to this disclosure may have a bandwidth of 1.75 GHzwith center frequency 8.125 GHz and thus its fractional bandwidth is1.75/8.125 or 21.5%.

In some aspects, the apparatus may be implemented in or comprise aheadset, medical device, microphone, biometric sensor, heart ratemonitor, pedometer, EKG device, user I/O device, watch, remote control,switch, tire pressure monitor, entertainment device, computer,point-of-sale device, hearing aid, set-top box, cell phone, or a devicewith some form of wireless signaling capability. In some aspects, theapparatus may be implemented in or comprise an access point such as aWiFi node. For example, the access point may provide connectivity toanother network (e.g., a wide area network such as the Internet) via awired or wireless communication link.

Other aspects, advantages and novel features of the present disclosurewill become apparent from the following detailed description of thedisclosure when considered in conjunction with the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A illustrates a block diagram of an exemplary apparatus forgenerating an oscillating signal in accordance with some aspects of thedisclosure;

FIG. 1B illustrates a block diagram of an exemplary apparatus forgenerating an oscillating signal in accordance with some aspects of thedisclosure;

FIG. 1C illustrates a flow diagram of an exemplary method of generatingan oscillating signal in accordance with some aspects of the disclosure;

FIG. 2 illustrates a flow diagram of an exemplary method of calibratingan apparatus for generating an oscillating signal in accordance withsome aspects of the disclosure;

FIG. 3 illustrates a flow diagram of an exemplary method of enabling anddisabling an apparatus for generating an oscillating signal inaccordance with some aspects of the disclosure;

FIG. 4 illustrates a schematic diagram of an exemplary apparatus forgenerating an oscillating signal in accordance with some aspects of thedisclosure;

FIG. 5 illustrates a block and schematic diagram of an exemplarycommunication device in accordance with some aspects of the disclosure;

FIGS. 6A-D illustrate timing diagrams of various pulse modulationtechniques in accordance with some aspects of the disclosure; and

FIG. 7 illustrates a block diagram of various communication devicescommunicating with each other via various channels in accordance withsome aspects of the disclosure.

DETAILED DESCRIPTION

Various aspects of the disclosure are described below. It should beapparent that the teachings herein may be embodied in a wide variety offorms and that any specific structure, function, or both being disclosedherein are merely representative. Based on the teachings herein oneskilled in the art should appreciate that an aspect disclosed herein maybe implemented independently of any other aspects and that two or moreof these aspects may be combined in various ways. For example, anapparatus may be implemented or a method may be practiced using anynumber of the aspects set forth herein. In addition, such an apparatusmay be implemented or such a method may be practiced using otherstructure, functionality, or structure and functionality in addition toor other than one or more of the aspects set forth herein.

As an example of some of the above concepts, in some aspects, theinventive device or apparatus according to this disclosure comprises afirst circuit to generate an oscillating signal; a second circuit tosupply a first current to the first circuit; and a third circuit tosupply a second current to the first circuit, wherein the first andsecond currents are adapted to reduce a time duration for theoscillating signal to reach a defined steady-state condition. In otheraspects, the inventive apparatus may comprise a VCO that in turncomprises a single circuit adapted to generate an initial higher currentfor the oscillating circuit to accelerate the generation of a definedsteady-state oscillating signal, and a subsequent lower current for theoscillating circuit to sustain the generation of the definedsteady-state oscillating signal. The term “defined” as used herein maybe construed as “predetermined”, “predefined”, or “dynamically defined.”

FIG. 1A illustrates a block diagram of an exemplary apparatus 100 forgenerating an oscillating signal in accordance with some aspects of thedisclosure. The apparatus 100 is capable of generating an oscillatingsignal having a frequency dictated by a frequency input. In some aspect,the apparatus 100 may be configured or comprise a voltage controlledoscillator (VCO). The apparatus 100 comprises an integrated circuit togenerate first and second currents to accelerate the oscillating signalin reaching a defined steady-state condition from a start up condition.As discussed in more detail below, this is particularly useful forcommunication devices that use relatively low duty cycle pulsemodulation to establish communication channels. In this regard, theapparatus 100 begins generating the oscillating signal at approximatelythe beginning of the pulse and stops generating the oscillating signalat approximately the end of the pulse.

More specifically, the apparatus 100 comprises an integrated circuit(IC) 102 for generating a first current (e.g., a quiescent biascurrent), an IC 104 for generating a second current (e.g., a boost biascurrent), and an IC 106 for generating an oscillating signal 106.Although in this example, the ICs 102, 104, and 106 are shown asseparate ICs, it shall be understood that any of these may be configuredinto one or more ICs. The IC 106 generates an oscillating signal (e.g.,a sinusoidal signal) cycling at a frequency dictated by a frequencyinput. The IC 102 provides a first current to the IC 106 during start-upand steady-state conditions. The IC 104 provides a second current to theIC 106 during start up to accelerate the oscillating signal in reachinga defined steady-state condition. The defined steady-state condition mayspecify a stability requirement for the frequency and/or the amplitudeof the oscillating signal.

FIG. 1B illustrates a block diagram of an exemplary apparatus 150 forgenerating an oscillating signal in accordance with some aspects of thedisclosure. The apparatus 150 may be a more detailed implementation ofthe apparatus 100 previously discussed. In particular, the apparatus 150comprises a circuit 152 for generating a first current (e.g., aquiescent bias current), a circuit 154 for generating a second current(e.g., a boost bias current), an output steady-state detector 156, afrequency calibration unit 158, a circuit 160 for generating anoscillating signal (“oscillating circuit”), and an ambient temperaturesensor 162. The circuit 160 generates an oscillating signal cycling witha frequency that is tunable via a frequency tuning word received fromthe frequency calibration unit 158.

The frequency calibration unit 158 receives a frequency input word thatspecifies the frequency or frequency range of the oscillating signal,and measures the actual frequency of the oscillating signal from asample received from the output of the oscillating circuit 160. Based onthe frequency input word and the measured frequency, the frequencycalibration unit 158 generates a frequency tuning word that tunes theoscillating circuit 160 so that the frequency of the oscillating signalis within the requirement specified by the frequency input word. Thefrequency calibration unit 158 may calibrate the frequency of theoscillating signal upon power up, upon receiving a new frequency inputword, and/or upon detecting a change in ambient temperature that exceedsa defined threshold. The frequency calibration unit 158 receivestemperature information from the ambient temperature sensor 162.

The circuit 152 provides a first current to the oscillating circuit 160during start-up and steady-state conditions. The boost bias circuit 154provides a second current to the oscillating circuit 160 during start upto accelerate the oscillating signal reaching a defined steady-statecondition from a start up condition. The output steady-state detector156 samples the output of the oscillating circuit 160 in order todisable the circuit 154 when the detector 156 detects the definedsteady-state condition of the oscillating signal. Thus, the circuit 154is used during start up of the oscillating circuit 160 in order toreduce the time for the oscillating signal to reach the definedsteady-state. As previously discussed, the defined steady-statecondition may specify a stability requirement for the frequency and/orthe amplitude of the oscillating signal.

FIG. 1C illustrates a flow diagram of an exemplary method 170 ofgenerating an oscillating signal in accordance with some aspects of thedisclosure. According to the method 170, a first current (e.g., aquiescent bias current) is generated (block 171). Additionally, a secondcurrent (e.g., a boost bias current) is generated (block 174). Then, anoscillating signal is generated in response to the first and secondcurrents (block 176).

FIG. 2 illustrates a flow diagram of an exemplary method 200 ofcalibrating the apparatus 150 in accordance with some aspects of thedisclosure. According to the method 200, the frequency calibration unit158 detects power up of a unit (e.g., a communication device) thatincorporates the apparatus 150 (block 202). Then, the frequencycalibration unit 158 may receive a frequency input word that specifies afrequency or frequency range for the oscillating signal generated by theoscillating circuit 160 (block 204). In particular applications, asdiscussed in more detail below, the defined frequency range may berelatively large. That is, the output frequency of the apparatus 150need not be that accurate. For example, the specified frequency rangemay be as large as one percent of a defined center frequency.

Then, the frequency calibration unit 158 enables the oscillating circuit160 by sending an oscillator enable signal to the circuits 152 and 154to provide the first and second currents to the oscillating circuit 160(block 206). The frequency calibration unit 158 then generates an inputfrequency tuning word to cause the oscillating circuit 160 to generatean oscillating signal that cycles with an initial frequency (block 208).The frequency calibration unit 158 measures the frequency of theoscillating signal from the sampled output of the oscillating circuit160 (block 210).

The frequency calibration unit 158 then determines whether the measuredfrequency of the oscillating signal is within the defined range (block212). If the frequency calibration unit 158 determines that the measuredfrequency is above the defined range, the frequency calibration unit 158decrements the frequency tuning word so as to decrease the frequency ofthe oscillating signal (block 214). If, on the other hand, the frequencycalibration unit 158 determines that the measured frequency is below thedefined range, the frequency calibration unit 158 increments the inputfrequency tuning word so as to increase the frequency of the oscillatingsignal (block 216). After performing operation 214 or 216, the frequencycalibration unit 158 performs another frequency measurement andcomparison per operations 210 and 212, respectively.

If, in operation 212, the frequency calibration unit 158 determines thatthe measured frequency of the oscillating signal is within the definedrange, the frequency calibration unit 158 stores the frequency tuningword (block 218). The frequency calibration unit 158 then sends adisable oscillator signal to the circuit 152 to cease generating thefirst current so as to disable the oscillating circuit (block 220).Note, that the frequency calibration unit 158 need not send the disableoscillator signal to the circuit 154 because the output steady-statedetector 156 may have already disabled the circuit 154 after detectingthe defined steady-state condition of the oscillating signal.

As previously discussed, the frequency calibration unit 158 may performa frequency calibration of the oscillating circuit 160 when it detectsan ambient temperature change that exceeds a defined threshold or whenit receives a new frequency input word. In this regard, the frequencycalibration unit 158 receives ambient temperature information from theambient temperature sensor 162 (block 222). The frequency calibrationunit 158 then determines whether the current ambient temperature haschanged from the ambient temperature associated with the previousfrequency calibration by a defined threshold (block 224). If thefrequency calibration determines that the change in the ambienttemperature exceeds the threshold, the frequency calibration unit 158enables the oscillating circuit 160 (block 228) and performs anothercalibration routine as specified by operations 210 through 220.

If, on the other hand, the frequency calibration unit 158 determinesthat the change in the ambient temperature does not exceed thethreshold, the frequency calibration unit 158 determines whether it hasreceived a new frequency input word (block 226). If the frequencycalibration unit 158 has not received a new frequency input word, it mayreturn to operation 222 to determine whether the ambient temperature haschanged beyond the threshold. If, on the other hand, the frequencycalibration unit 158 received a new frequency input word, the frequencycalibration unit 158 enables the oscillating circuit 160 again (block228) and performs another calibration routine as specified by operations210 through 220. The frequency calibration unit 158 may proactively testfor the ambient temperature change and/or the new frequency input word,or may merely react to it via an interrupt operation.

FIG. 3 illustrates a flow diagram of an exemplary method 300 of enablingand disabling the apparatus 150 in accordance with some aspects of thedisclosure. According to the method 300, the apparatus 150 receives anoscillator enable signal from an external device (block 302). Forexample, the external device may be a pulse modulation device that isused to establish a communications channel by use of PDMA or PDMmodulation techniques. In this regard, the apparatus 150 is turned onfor only approximately the duration of a pulse. Thus, the leading edgeof the pulse may serve as the oscillator enable signal.

In response to the oscillator enable signal, the current generatingcircuits 152 and 154 are activated (blocks 304 and 306) in any order orsimultaneously. The activation of the circuits 152 and 154 causes theoscillating circuit 160 to begin generating an oscillating signal. Aspreviously discussed, the circuit 154 assists in reducing the time forthe oscillating signal to reach a defined steady-state condition. Thedefined steady-state condition may be based on the stability of theamplitude and/or frequency of the oscillating signal. For example, thedefined steady-state condition may specify an amplitude stability of theoscillating signal of not varying more than 15 percent. The definedsteady-state condition may also specify a frequency stability of theoscillating signal of not varying more than one (1) percent.

The output steady-state detector 156 measures the steady-state conditionof the oscillating signal generated by the oscillating circuit 160(block 308). The output steady-state detector 156 then determineswhether the steady-state condition of the oscillating signal meets therequirements of the defined steady-state condition (block 310). If thesteady-state condition of the oscillating signal does not meet therequirements, the output steady-state detector 156 continues to performthe operations 308 and 310 until the defined steady-state condition ismet. When the output steady-state detector 156 determines that thesteady-state condition of the oscillating signal meets specification,the output steady-state detector 156 disables the circuit 154 (block312). In this way, the circuit 154 is only enabled to accelerate theoscillating signal in reaching the defined steady-state condition,thereby conserving energy during steady-state oscillations.

The apparatus 150 may then receive an oscillator disable signal from theexternal device (block 314). As previously discussed, the externaldevice may disable the apparatus 150 at the end of a pulse. Accordingly,the oscillator disable signal may be the trailing edge of the pulse. Inresponse to the oscillator disable signal, the circuit 152 isdeactivated (block 316). One purpose of disabling the circuit 152 is tosave power. However, the persistence of oscillation could be used toshut off the circuit 152 early, thereby saving even more power.

FIG. 4 illustrates a schematic diagram of an exemplary apparatus 400 forgenerating an oscillating signal in accordance with some aspects of thedisclosure. The apparatus 400 may be a detailed implementation of any ofthe aspects previously discussed. The apparatus 400 comprises anoscillating circuit 412 including an inductor 414 coupled in parallelwith a switched capacitor bank 416 and a negative resistance generator418. The apparatus 400 further comprises a frequency calibration circuit410 that is adapted to calibrate the frequency of the oscillating signalgenerated by the oscillating circuit 412. More specifically, thefrequency calibration circuit 410 generates a digital frequency wordthat selects which capacitors of the switched capacitor bank 416 arecoupled in parallel with the inductor 414 and the negative resistancegenerator 418, thereby controlling the frequency of the oscillatingsignal. The frequency calibration circuit 410 may include a counter (notshown) to count the periods of the oscillating signal in order tomeasure its frequency for tuning purposes.

The apparatus 400 further comprises a direct current (DC) power supply410, a first controllable current source 404, and a quiescent DC biascircuit 402. The power supply 409 supplies power to the firstcontrollable current source 404. In response to receiving an enablesignal, the quiescent DC bias circuit 402 controls the quiescent biascurrent that is applied to the oscillating circuit 412 by the firstcontrollable current source 404. The quiescent bias current is used tostart up and maintain the oscillating circuit 412 generating theoscillating signal.

The apparatus 400 further comprises a boost bias circuit 422, an outputsteady-state detector 420, a controllable amplifier 424, and a secondcontrollable current source 408. The power supply 409 supplies power tothe second controllable current source 408. In response to receiving theenable signal, the boost bias circuit 422 enables generates a boost biascurrent that is applied to the oscillating circuit 412 via thecontrollable amplifier 424 and the second controllable current source408. As previously discussed, the boost bias circuit 422 assists inreducing the time for the oscillating signal to reach a definedsteady-state condition. The output steady-state detector 420 is coupledto the oscillating circuit 412 to determine the steady-state conditionof the oscillating signal. When the output steady-state detector 420determines that the amplitude, frequency or both the amplitude andfrequency of the oscillating signal meet a defined specification, theoutput steady-state detector 420 disables the controllable amplifier 424so that the boost bias current is no longer applied to the oscillatingcircuit 412.

FIG. 5 illustrates a block diagram of an exemplary communication device500 that uses one or more apparatuses for an oscillating signal as localoscillators (LOs) in accordance with some aspects of the disclosure. Thecommunication device 500 comprises a receiver portion including a lownoise amplifier (LNA) 502, a mixer 504, a receiver local oscillator (LO)510, a baseband amplifier 506, and an energy detector 508. Thecommunication device 500 further comprises a transmitter portionincluding a baseband amplifier 528, a mixer 526, a transmitter LO 522,and a power amplifier 524. The communication device 500 furthercomprises an antenna 512, and a switch 514 to selectively isolate thetransmitter portion from the receiver portion during transmission.Additionally, the communication device 500 comprises a baseband unit520, a channel controller 518, and a pulse modulator 516. The basebandunit 520 processes baseband signals received from the receiver portion,and processes baseband signals for transmission by the transmitterportion.

The pulse modulator 516 is coupled to the receiver LO 510 to enable thereceiver LO at particular instances defined by pulses in order toestablish a receiving communication channel (e.g., an ultra-wide band(UWB) communication channel) using pulse division multiple access(PDMA), pulse division multiplexing (PDM), or other type of pulsemodulation. The pulse modulator 516 is also coupled to the transmitterLO 520 to enable the transmitter LO at particular instances defined bypulses in order to establish a transmitting communication channel (e.g.,an ultra-wide band (UWB) communication channel) using PDMA, PDM, orother type of pulse modulation. The transmitting and receiving channelsmay be established concurrently, although the channels may be orthogonalso as not to interfere with each other. An ultra-wide band (UWB))channel may be defined as a channel having a fractional bandwidth on theorder of 20% or more, has a bandwidth on the order of 500 MHz or more,or has a fractional bandwidth on the order of 20% or more and has abandwidth on the order of 500 MHz or more. The fractional bandwidth is aparticular bandwidth associated with a device divided by its centerfrequency. For example, a device according to this disclosure may have abandwidth of 1.75 GHz with center frequency 8.125 GHz and thus itsfractional bandwidth is 1.75/8.125 or 21.5%.

The channel controller 518 is coupled to the pulse modulator 516 inorder to establish the receiving and transmitting communication channelsby pulse modulation techniques as discussed in more detail below. Thechannel controller 518 is coupled to the switch 514 to set the switch toreceive mode where it couples the antenna 514 to the LNA 502 or set theswitch to the transmit mode where it couples the power amplifier 524 tothe antenna 512. If the communication device 500 is configured as awireless device, such as an IEEE 802.11 or 802.15 related wirelessdevice, the antenna 504 serves as an interface to a wireless medium forwirelessly transmitting and receiving information from other wirelessdevice.

Using pulse modulation techniques to enable and disable the transmitterand receiver, improved power efficiency may be achieved for thecommunication device 500. For example, during times when the transmitteris not transmitting and receiver is not receiving, these devices may beoperated in low or no power mode to conserve power, such as powerprovided by a battery. With regard to the transmission of data, forexample, data occupying a frequency bandwidth is transmitted during afirst time period within the time interval, wherein when the data istransmitted during the first time interval varies such that thevariation is associated with at least two time intervals, and powerconsumption of some components of the communication device 500 isreduced during at least a second time period within the interval.

FIG. 6A illustrates different channels (channels 1 and 2) defined withdifferent pulse repetition frequencies (PRF) as an example of a PDMAmodulation. Specifically, pulses for channel 1 have a pulse repetitionfrequency (PRF) corresponding to a pulse-to-pulse delay period 602.Conversely, pulses for channel 2 have a pulse repetition frequency (PRF)corresponding to a pulse-to-pulse delay period 604. This technique maythus be used to define pseudo-orthogonal channels with a relatively lowlikelihood of pulse collisions between the two channels. In particular,a low likelihood of pulse collisions may be achieved through the use ofa low duty cycle for the pulses. For example, through appropriateselection of the pulse repetition frequencies (PRF), substantially allpulses for a given channel may be transmitted at different times thanpulses for any other channel. The channel controller 518 and pulseposition modulator 516 may be configured to set up a pulse repetitionfrequency (PRF) modulation.

The pulse repetition frequency (PRF) defined for a given channel maydepend on the data rate or rates supported by that channel. For example,a channel supporting very low data rates (e.g., on the order of a fewkilobits per second or Kbps) may employ a corresponding low pulserepetition frequency (PRF). Conversely, a channel supporting relativelyhigh data rates (e.g., on the order of a several megabits per second orMbps) may employ a correspondingly higher pulse repetition frequency(PRF).

FIG. 6B illustrates different channels (channels 1 and 2) defined withdifferent pulse positions or offsets as an example of a PDMA modulation.Pulses for channel 1 are generated at a point in time as represented byline 606 in accordance with a first pulse offset (e.g., with respect toa given point in time, not shown). Conversely, pulses for channel 2 aregenerated at a point in time as represented by line 608 in accordancewith a second pulse offset. Given the pulse offset difference betweenthe pulses (as represented by the arrows 610), this technique may beused to reduce the likelihood of pulse collisions between the twochannels. Depending on any other signaling parameters that are definedfor the channels (e.g., as discussed herein) and the precision of thetiming between the devices (e.g., relative clock drift), the use ofdifferent pulse offsets may be used to provide orthogonal orpseudo-orthogonal channels. The channel controller 518 and pulseposition modulator 516 may be configured to set up a position or offsetmodulation.

FIG. 6C illustrates different channels (channels 1 and 2) defined withdifferent timing hopping sequences. For example, pulses 612 for channel1 may be generated at times in accordance with one time hopping sequencewhile pulses 614 for channel 2 may be generated at times in accordancewith another time hopping sequence. Depending on the specific sequencesused and the precision of the timing between the devices, this techniquemay be used to provide orthogonal or pseudo-orthogonal channels. Forexample, the time hopped pulse positions may not be periodic to reducethe possibility of repeat pulse collisions from neighboring channels.The channel controller 518 and pulse position modulator 516 may beconfigured to set up a time hopping modulation.

FIG. 6D illustrates different channels defined with different time slotsas an example of a PDM modulation. Pulses for channel L1 are generatedat particular time instances. Similarly, pulses for channel L2 aregenerated at other time instances. In the same manner, pulse for channelL3 are generated at still other time instances. Generally, the timeinstances pertaining to the different channels do not coincide or may beorthogonal to reduce or eliminate interference between the variouschannels. The channel controller 518 and pulse position modulator 516may be configured to set up the PDM modulation.

It should be appreciated that other techniques may be used to definechannels in accordance with a pulse modulation schemes. For example, achannel may be defined based on different spreading pseudo-random numbersequences, or some other suitable parameter or parameters. Moreover, achannel may be defined based on a combination of two or more parameters.

FIG. 7 illustrates a block diagram of various ultra-wide band (UWB)communication devices communicating with each other via various channelsin accordance with some aspects of the disclosure. For example, UWBdevice 1 702 is communicating with UWB device 2 704 via two concurrentUWB channels 1 and 2. UWB device 702 is communicating with UWB device 3706 via a single channel 3. And, UWB device 3 706 is, in turn,communicating with UWB device 4 708 via a single channel 4. Otherconfigurations are possible.

Any of these apparatuses described herein may take various forms. Forexample, in some aspects, the apparatus may be implemented in orcomprise a phone (e.g., a cellular phone), a personal data assistant(“PDA”), a headset (e.g., a headphone, en earpiece, etc.), a microphone,a medical device (e.g., a biometric sensor, a heart rate monitor, apedometer, an EKG device, etc.), a biometric sensor, a heart ratemonitor, a pedometer, an EKG device, a user I/O device, a watch, aremote control, a switch, a light switch, a keyboard, a mouse, a tirepressure monitor, an entertainment device (e.g., a music or videodevice), a computer, a point-of-sale device, a hearing aid, a set-topbox, or a device with some form of wireless signaling capabilities.Moreover, these apparatuses may have different power and datarequirements. In some aspects, any apparatus described herein may beadapted for use in low power applications (e.g., through the use of apulse-based signaling scheme and low duty cycle modes), and may supporta variety of data rates including relatively high data rates (e.g.,through the use of high-bandwidth pulses). In some aspects, any of theapparatuses described herein may be implemented in or comprise an accesspoint such as a Wi-Fi node. For example, such an apparatus may provideconnectivity to another network (e.g., a wide area network such as theInternet) via a wired or wireless communication link.

Any of these apparatuses may include various components that performfunctions bases on signals transmitted or received via the wirelesscommunication link. For example, a headset may include a transduceradapted to provide an audible output based on a signal received via thewireless communication link established by a receiver responsive to alocal oscillator incorporating any of the aspects described herein. Awatch may include a display adapted to provide a visual output based ona signal received via the wireless communication link by a receiverresponsive to a local oscillator incorporating any of the aspectsdescribed herein. A medical device may include a sensor adapted togenerate at least sensed signal or sensed data to be transmitted via thewireless communication link by a transmitter responsive to a localoscillator incorporating any of the aspects described herein.

Various aspects of the disclosure have been described above. It shouldbe apparent that the teachings herein may be embodied in a wide varietyof forms and that any specific structure, function, or both beingdisclosed herein is merely representative. Based on the teachings hereinone skilled in the art should appreciate that an aspect disclosed hereinmay be implemented independently of any other aspects and that two ormore of these aspects may be combined in various ways. For example, anapparatus may be implemented or a method may be practiced using anynumber of the aspects set forth herein. In addition, such an apparatusmay be implemented or such a method may be practiced using otherstructure, functionality, or structure and functionality in addition toor other than one or more of the aspects set forth herein. As an exampleof some of the above concepts, in some aspects concurrent channels maybe established based on pulse repetition frequencies. In some aspectsconcurrent channels may be established based on pulse position oroffsets. In some aspects concurrent channels may be established based ontime hopping sequences. In some aspects concurrent channels may beestablished based on pulse repetition frequencies, pulse positions oroffsets, and time hopping sequences.

Those of skill in the art would understand that information and signalsmay be represented using any of a variety of different technologies andtechniques. For example, data, instructions, commands, information,signals, bits, symbols, and chips that may be referenced throughout theabove description may be represented by voltages, currents,electromagnetic waves, magnetic fields or particles, optical fields orparticles, or any combination thereof.

Those of skill would further appreciate that the various illustrativelogical blocks, modules, processors, means, circuits, and algorithmsteps described in connection with the aspects disclosed herein may beimplemented as electronic hardware (e.g., a digital implementation, ananalog implementation, or a combination of the two, which may bedesigned using source coding or some other techniques), various forms ofprogram or design code incorporating instructions (which may be referredto herein, for convenience, as “software” or a “software module”), orcombinations of both. To clearly illustrate this interchangeability ofhardware and software, various illustrative components, blocks, modules,circuits, and steps have been described above generally in terms oftheir functionality. Whether such functionality is implemented ashardware or software depends upon the particular application and designconstraints imposed on the overall system. Skilled artisans mayimplement the described functionality in varying ways for eachparticular application, but such implementation decisions should not beinterpreted as causing a departure from the scope of the presentdisclosure.

The various illustrative logical blocks, modules, and circuits describedin connection with the aspects disclosed herein may be implementedwithin or performed by an integrated circuit (“IC”) The IC may comprisea general purpose processor, a digital signal processor (DSP), anapplication specific integrated circuit (ASIC), a field programmablegate array (FPGA) or other programmable logic device, discrete gate ortransistor logic, discrete hardware components, electrical components,optical components, mechanical components, or any combination thereofdesigned to perform the functions described herein, and may executecodes or instructions that reside within the IC, outside of the IC, orboth. A general purpose processor may be a microprocessor, but in thealternative, the processor may be any conventional processor,controller, microcontroller, or state machine. A processor may also beimplemented as a combination of computing devices, e.g., a combinationof a DSP and a microprocessor, a plurality of microprocessors, one ormore microprocessors in conjunction with a DSP core, or any other suchconfiguration.

It is understood that any specific order or hierarchy of steps in anydisclosed process is an example of a sample approach. Based upon designpreferences, it is understood that the specific order or hierarchy ofsteps in the processes may be rearranged while remaining within thescope of the present disclosure. The accompanying method claims presentelements of the various steps in a sample order, and are not meant to belimited to the specific order or hierarchy presented.

The steps of a method or algorithm described in connection with theaspects disclosed herein may be embodied directly in hardware, in asoftware module executed by a processor, or in a combination of the two.A software module (e.g., including executable instructions and relateddata) and other data may reside in a data memory such as RAM memory,flash memory, ROM memory, EPROM memory, EEPROM memory, registers, a harddisk, a removable disk, a CD-ROM, or any other form of computer-readablestorage medium known in the art. A sample storage medium may be coupledto a machine such as, for example, a computer/processor (which may bereferred to herein, for convenience, as a “processor”) such theprocessor can read information (e.g., code) from and write informationto the storage medium. A sample storage medium may be integral to theprocessor. The processor and the storage medium may reside in an ASIC.The ASIC may reside in user equipment. In the alternative, the processorand the storage medium may reside as discrete components in userequipment. Moreover, in some aspects any suitable computer-programproduct may comprise a computer-readable medium comprising codesrelating to one or more of the aspects of the disclosure. In someaspects a computer program product may comprise packaging materials.

While the invention has been described in connection with variousaspects, it will be understood that the invention is capable of furthermodifications. This application is intended to cover any variations,uses or adaptation of the invention following, in general, theprinciples of the invention, and including such departures from thepresent disclosure as come within the known and customary practicewithin the art to which the invention pertains.

1. An apparatus for generating an oscillating signal, comprising: afirst circuit to generate an oscillating signal; a second circuit tosupply a first current to the first circuit; and a third circuit tosupply a second current to the first circuit, wherein the first andsecond currents are adapted to reduce a time duration for theoscillating signal to reach a defined steady-state condition.
 2. Theapparatus of claim 1, wherein the first circuit comprises: a tankcircuit; and a negative resistance generator coupled to the tankcircuit.
 3. The apparatus of claim 2, wherein the tank circuitcomprises: an inductive device; and a capacitive device coupled inparallel with the inductive device.
 4. The apparatus of claim 3, whereinthe capacitive device comprises a programmable switched capacitor bank.5. The apparatus of claim 1, further comprising a steady-state detectoradapted to disable the third circuit from supplying the second currentto the first circuit in response to detecting the defined steady-statecondition of the oscillating signal.
 6. The apparatus of claim 1,wherein the defined steady-state condition is based on an amplitudestability of the oscillating signal.
 7. The apparatus of claim 6,wherein the defined steady-state condition is based on the amplitude ofthe oscillating signal not varying more than 15 percent.
 8. Theapparatus of claim 1, wherein the defined steady-state condition isbased on a frequency stability of the oscillating signal.
 9. Theapparatus of claim 8, wherein the defined steady-state condition isbased on the frequency of the oscillating signal not varying more thanone (1) percent.
 10. The apparatus of claim 1, further comprising afrequency calibration unit adapted to tune the first circuit so that theoscillating signal cycles within a defined frequency range.
 11. Theapparatus of claim 10, wherein the defined frequency range is equal toone (1) percent of a defined center frequency.
 12. The apparatus ofclaim 10, wherein the frequency calibration unit is adapted to tune thefirst circuit upon power up of the apparatus, upon detecting an ambienttemperature change above a defined threshold, or upon receiving a newfrequency word for the first circuit.
 13. The apparatus of claim 1,further comprises a transceiver responsive to the oscillating signal toestablish at least one ultra-wide band communications channel withanother apparatus.
 14. The apparatus of claim 13, wherein eachultra-wide band channel has a fractional bandwidth on the order of 20%or more, has a bandwidth on the order of 500 MHz or more, or has afractional bandwidth on the order of 20% or more and has a bandwidth onthe order of 500 MHz or more.
 15. A method of generating an oscillatingsignal, comprising: generating a first current; generating a secondcurrent; and generating an oscillating signal in response to the firstand second current, wherein the second current reduces a time durationfor the oscillating signal to reach a defined steady-state condition.16. The method of claim 15, wherein generating the oscillating signal isaccomplished by: a tank circuit; and a negative resistance generatorcoupled to the tank circuit.
 17. The method of claim 16, wherein thetank circuit comprises: an inductive device; and a capacitive devicecoupled in parallel with the inductive device.
 18. The method of claim17, wherein the capacitive device comprises a programmable switchedcapacitor bank.
 19. The method of claim 15, further comprising disablingthe generating of the second current in response to detecting thedefined steady-state condition of the oscillating signal.
 20. The methodof claim 15, wherein the defined steady-state condition is based on anamplitude stability of the oscillating signal.
 21. The method of claim20, wherein the defined steady-state condition is based on the amplitudeof the oscillating signal not varying more than 15 percent.
 22. Themethod of claim 15, wherein the defined steady-state condition is basedon a frequency stability of the oscillating signal.
 23. The method ofclaim 22, wherein the defined steady-state condition is based on thefrequency of the oscillating signal not varying more than one (1)percent.
 24. The method of claim 15, further comprising calibrating theoscillating signal so that it cycles within a defined frequency range.25. The method of claim 24, wherein the defined frequency range is equalto one (1) percent of a defined center frequency.
 26. The method ofclaim 24, wherein calibrating the oscillating signal is performed inresponse to detecting power up, to detecting an ambient temperaturechange above a defined threshold, or to receiving a new frequency word.27. The method of claim 15, further comprising establishing at least oneultra-wide band communications channel using the oscillating signal. 28.The method of claim 27, wherein each ultra-wide band channel has afractional bandwidth on the order of 20% or more, has a bandwidth on theorder of 500 MHz or more, or has a fractional bandwidth on the order of20% or more and has a bandwidth on the order of 500 MHz or more.
 29. Anapparatus for generating an oscillating signal, comprising: means forgenerating an oscillating signal; means for supplying a first current tothe oscillating signal generating means; and means for supplying asecond current to the oscillating signal generating means, wherein thefirst and second currents are adapted to reduce a time duration for theoscillating signal to reach a defined steady-state condition.
 30. Theapparatus of claim 29, wherein the oscillating signal generating meanscomprises: a tank circuit; and a negative resistance generator coupledto the tank circuit.
 31. The apparatus of claim 30, wherein the tankcircuit comprises: an inductive device; and a capacitive device coupledin parallel with the inductive device.
 32. The apparatus of claim 31,wherein the capacitive device comprises a programmable switchedcapacitor bank.
 33. The apparatus of claim 29, further comprising meansfor disabling the second current supplying means from supplying thesecond current in response to detecting the defined steady-statecondition of the oscillating signal.
 34. The apparatus of claim 29,wherein the defined steady-state condition is based on an amplitudestability of the oscillating signal.
 35. The apparatus of claim 34,wherein the defined steady-state condition is based on the amplitude ofthe oscillating signal not varying more than 15 percent.
 36. Theapparatus of claim 29, wherein the defined steady-state condition isbased on a frequency stability of the oscillating signal.
 37. Theapparatus of claim 36, wherein the defined steady-state condition isbased on the frequency of the oscillating signal not varying more thanone (1) percent.
 38. The apparatus of claim 29, further comprising meansfor calibrating the oscillating signal generating means so that theoscillating signal cycles within a defined frequency range.
 39. Theapparatus of claim 38, wherein the defined frequency range is equal toone percent of a defined center frequency.
 40. The apparatus of claim38, wherein the calibration means is adapted to calibrate theoscillating signal generating means upon power up of the apparatus, upondetecting an ambient temperature change above a defined threshold, orupon receiving a new frequency word for the oscillating signalgenerating means.
 41. The apparatus of claim 29, further comprisingmeans for establishing at least one ultra-wide band communicationschannel with another apparatus using the oscillating signal.
 42. Theapparatus of claim 41, wherein each ultra-wide band channel has afractional bandwidth on the order of 20% or more, has a bandwidth on theorder of 500 MHz or more, or has a fractional bandwidth on the order of20% or more and has a bandwidth on the order of 500 MHz or more.
 43. Acomputer program product for generating an oscillating signalcomprising: a computer readable medium comprising codes executable by atleast one computer to: generate an oscillating signal; supply a firstcurrent to produce the generation of the oscillating signal; and supplya second current to reduce a time duration for the oscillating signal toreach a defined steady-state condition.
 44. A headset for performing anoperation based on distance, comprising: a first circuit to generate anoscillating signal; a second circuit to supply a first current to thefirst circuit; a third circuit to supply a second current to the firstcircuit, wherein the first and second currents are adapted to reduce atime duration for the oscillating signal to reach a defined steady-statecondition; a transducer adapted to generate at least one audio signal;and a transmitter adapted to combine the at least one audio signal withthe oscillating signal, and transmit the combined signal.
 45. A watchfor performing an operation based on distance, comprising: a firstcircuit to generate an oscillating signal; a second circuit to supply afirst current to the first circuit; a third circuit to supply a secondcurrent to the first circuit, wherein the first and second currents areadapted to reduce a time duration for the oscillating signal to reach adefined steady-state condition; a receiver adapted to combine anincoming signal with the oscillating signal; and a display adapted toprovide a visual output based on the combined signal.
 46. A medicaldevice for performing an operation based on distance, comprising: afirst circuit to generate an oscillating signal; a second circuit tosupply a first current to the first circuit; a third circuit to supply asecond current to the first circuit, wherein the first and secondcurrents are adapted to reduce a time duration for the oscillatingsignal to reach a defined steady-state condition; a sensor adapted togenerate at least one sensed signal; and a transmitter adapted tocombine the at least one sensed signal and the oscillating signal andtransmit the combined signal over a wireless communication link.